Experiments for a Unit Operations in Food Engineering Course

A series of hands-on activities were developed to accompany a Unit Operations in Food Engineering course. The activities covered mechanical properties, the mechanical energy balance, and heat transfer. Each experiment was completed in a two-hour class period. Equipment for one group of students would cost approximately $50, assuming basic laboratory equipment is available. Total expenditures on supplies for the three labs were less than $100. Learning objectives, proposed assessment of student learning and specific details of the experiments are included for each experiment. Background Information: Junior chemical engineering students at Lafayette College take a Transport Phenomena course in the fall semester, where they learn the theory of momentum and heat transfer. In the spring, the students enroll in Applied Fluid Dynamics and Heat Transfer. This course covers practical applications of the theory, such as pump and heat exchanger sizing. The course has two weekly one-hour lecture times and one two-hour problem solving time. The students are also simultaneously enrolled in a Unit Operations laboratory where traditional experiments on pumps, heat exchangers and packed beds are performed. Due to enrollment growth, two sections of the applied course are offered each year, and due to student interest, one section focuses on unit operations in the food industry. The experiments described below were offered in the food unit operations section of the course – not as part of the Unit Operations laboratory course. Twelve to sixteen students enroll in this section each year. The course begins with information on physical properties of foods, including rheology, and electrical and mechanical properties. While these are not covered in a traditional unit operations course, they are a necessary foundation for this course, and are useful for any chemical engineer. The first experiment covers mechanical properties important to the food industry, providing background for the rest of the course. The next portion of the course covers the mechanical energy balance. Since most foods are non-Newtonian, the experiment introduced students to the categories and characterization of non-Newtonian fluids and the necessary modifications to the mechanical energy balance. The third portion of the class covers heat transfer in food preservation and cooking unit operations. The students were intrigued by the idea that during cooking and baking, the temperature of the food does not exceed the boiling point of water. This was illustrated and modeled with an experiment.